The invention relates to a detergent composition suitable for use in dish washing or laundry. The composition comprises a block copolymer. The composition according to the invention presents an increased cleaning and/or a decreased redeposition of fatty substances once they are removed from a substrate.
Typical detergent compositions, as well dish washing compositions and laundry compositions, are based on detersive surfactants. Detersive surfactants remove fatty substances from the product to be washed. Other compounds are usually added to modify the properties or the compositions, for different purposes. Dish washing and laundry compositions are usually commercialized in a concentrate form, and diluted with water by consumers at time of use. Thus, dish washing and laundry compositions comprise usually more than 15% surfactants in addition to other additives.
Use of the compositions may be very different, depending of the consumer. Some consumers use the compositions in highly dilute form while some, especially in hand dish washing, almost use it in the concentrate form.
Performance of the detersive surfactants depends on the chemical structure of the compounds used as surfactants, and partly on their concentration and relative composition. However, there is usually a concentration value above which using more detersive surfactant is not more effective. There is a need for improving the cleaning efficiency of detersive surfactant composition, either by allowing the use of less surfactant with an equivalent effect, or by using the same amount of surfactant and delivering an increased effect.
Adding some compounds to increase the cleaning efficiency of detersive surfactants is known. Document WO 98/28393 for example describes using diamines.
Fatty substances form droplets in an aqueous phase. Coalescence of these droplets may occur, and a re-deposition may occur on the substrate, which is undesirable. Such a re-deposition may cause the users to think washing performance was not good. Some visible traces may also remain on the substrate because of coalescence and re-deposition.
Adding some compounds to prevent coalescence and re-deposition is known. Document WO 98/26036 for example describes using selected polymers having a hydrophilic backbone and hydrophobic side chains.
Many documents describe adding polymers to modify various properties of detergent compositions.
Document WO 00/71660 describes using block copolymers comprising a cationic block and a neutral block as a suds booster in hand dish washing compositions.
Document WO 00/12660 teaches suppression of lamellar mesophases of surfactants in making microemulsions by adding a diblock or triblock hydrophilic-hydrophobic copolymer. Suppression of lamellar mesophases is referred in this document as “increasing the efficiency of surfactants”. Experiments described in this document have been performed with a polyisoprene-block-polyethylene copolymer. Concentrations of surfactants and copolymers in the experiments are comprised between 4% of surfactant, with a ratio copolymer/(surfactant+copolymer) of 12%, and 18% of surfactant, with a ratio copolymer/(surfactant+copolymer) of 1.5%.
However, detergent compositions, when used usually do not present lamellar mesophases. Formation of lamellar mesophases occurs in very particular conditions, depending on temperature and surfactant concentration. When a detergent composition is diluted, the concentration of the detersive surfactant is usually below 4%, and even below 1%. Moreover, the block copolymer disclosed in document WO 00/12660 is difficult to formulate in a concentrate detergent composition to be diluted for use. Said block copolymer may phase separate from other compounds of the composition, and thus confer upon the composition poor mixing and stability, which affects its performance and aesthetic properties.